DEVICE FOR AUTOMATIC MEASURING AND CUTTING PIECES OF SHEET MATERIAL

摘要

1475594 Feeding webs G D SpA 15 July 1974 [21 Sept 1973] 31211/74 Heading B8R An apparatus for feeding a wrapping machine in which wrappers are severed from webs by a cutter C1, C2 comprises a pair of web rolls B1, B2 which are used alternately to supply webs N1, N2 by means of rollers r1, r2 or r11, r21 and R1, R2 to the cutter C1, C2 whereby one roll B1, B2 is in a stand-by position and its web N1, N2 is fed with its leading edge Y, Y1 closely following in an abutting position the trailing edge of the expiring web N1, N2. In operation the trailing edge of the expiring web N1, N2 is sensed by a device F1, F2 which causes a contact (T1, T2, Fig. 2) to be closed and a signal to be fed to a second input of an AND-gate associated with a memory producing pulses which correspond to the distance between auxiliary cutters c1 c2; c11, c21 and the leading edges Y, Y1, the distance in turn corresponding to an integral number of sheets S forming the wrappers. The memory is used to drive, e.g. the auxiliary cutter e1, e2 when the web roll B1 has expired and following a preset number of pulses to drive the rollers r11, r21, to feed the web N2 from the replacement web roll B2 in an abutting relationship with the trailing edge of the expiring web N1. In a modification the cutter C1, C2 may be dispensed with and the cutters c1, c2; c11, c21 used alternately for cutting the webs N1, N2 into sheets S which are fed to a common location, e.g. the nip of rollers R1, R2.